Question
The elements in Group 17 tend to be extremely reactive. The elements in Group 18 are usually very stable.
What accounts for the difference in reactivity between the two groups?
A.
The Group 17 elements need one electron to fill their outer level. In the Group 18 elements, the outer level is already filled.
B.
The Group 17 elements have odd atomic numbers, meaning that their electrons are not paired. In the Group 18 elements, all the electrons exist in pairs.
C.
The Group 17 elements are mostly liquids and solids, while the Group 18 elements are gases. Because liquids and solids are denser, the atoms are close together and react more easily.
D.
The Group 17 elements have lighter nuclei, so they do not attract their electrons as strongly. The Group 18 elements have heavy nuclei that exert a strong attraction on their electrons.
What accounts for the difference in reactivity between the two groups?
A.
The Group 17 elements need one electron to fill their outer level. In the Group 18 elements, the outer level is already filled.
B.
The Group 17 elements have odd atomic numbers, meaning that their electrons are not paired. In the Group 18 elements, all the electrons exist in pairs.
C.
The Group 17 elements are mostly liquids and solids, while the Group 18 elements are gases. Because liquids and solids are denser, the atoms are close together and react more easily.
D.
The Group 17 elements have lighter nuclei, so they do not attract their electrons as strongly. The Group 18 elements have heavy nuclei that exert a strong attraction on their electrons.
Answers
Answered by
GPT-5 mini
A.
Group 17 (the halogens) have seven valence electrons and need one more to achieve a full valence shell (octet), so they readily gain an electron and are very reactive. Group 18 (the noble gases) already have complete valence shells, making them stable and largely unreactive.
(B, C, and D are incorrect for the reasons described: reactivity is not about odd/even electron pairing, physical state, or simply heavier nuclei in those groups.)
Group 17 (the halogens) have seven valence electrons and need one more to achieve a full valence shell (octet), so they readily gain an electron and are very reactive. Group 18 (the noble gases) already have complete valence shells, making them stable and largely unreactive.
(B, C, and D are incorrect for the reasons described: reactivity is not about odd/even electron pairing, physical state, or simply heavier nuclei in those groups.)